a) Field of the Invention
This invention relates to a storage box apparatus, which can be arranged, for example, in a detached house, a multiple dwelling house such as a condominium, a business building, a department store, a station, an airport or the like and can be used, for example, for keeping something delivered by a delivery serviceman of a home delivery service company, liquor store, laundry or the like or when a user sends out a package. In particular, the present invention is concerned with a storage box apparatus provided with one or more thermoelectric modules for enabling refrigeration, freezing and heating of one or more packages during storage.
b) Description of the Related Art
A system has been developed recently, in which a storage box apparatus is arranged in a multiple dwelling house such as a condominium. If no one is at a consignee's house when a home delivery serviceman visits there, he leaves a package in the storage box apparatus and also drops a delivery slip in a mail box of the consignee's house. When the consignee returns home, the consignee learns the delivery of the package from the delivery slip and then receives the package from the storage box apparatus.
Known examples of the storage box apparatus for use in the above system include those making use of flon and a compressor like ordinary electric refrigerators and those provided with refrigerating function by using a thermoelectric module.
However, those making use of a flon-type cooling medium involve an environmental problem such as ozone layer depletion by flon. Further, storage box apparatuses making use of flon and a compressor take long time until cooling is performed in an intermittent operation after they are kept out of operation for a relatively long time, because they first require a pre-stage of gas compression after they are switched on. Accordingly, a cooling system making use of one or more thermoelectric modules has been developed recently. As this system does not use flon gas, it has many advantages such that it is free from environmental disruption, it is excellent in cooling performance, it is free from the potential problem of gas leakage, it can be constructed into a smaller size with a longer service life owing to the use of semiconductors as primary components, and it does not require the pre-stage of gas compression and can immediately perform cooling upon energization.
FIG. 26 is a cooling characteristic diagram showing temperature control of a storage box apparatus of the flon/compressor type (preset interior temperature: +2.5.degree. C., curve X) and also temperature control of a storage box apparatus making use of a thermoelectric module (preset interior temperature: -0.2.degree. C., curve Y).
As is evident from this diagram, the cooling box apparatus of the flon/compressor type requires a substantial time until the preset temperature is reached after the temperature control is started, and during the temperature control, the interior temperature varies up and down considerably. In contrast, the storage box apparatus making use of the thermoelectric module reaches the preset temperature in a short time after the temperature control is started, and the interior temperature is then held practically constant, thereby leading to an advantage that the accuracy of the temperature control is good.
Storage box apparatuses making use of one or more thermoelectric transducers of the above-described type are conventionally known as they are disclosed, for example, in Japanese Patent Application Laid-Open (Kokai) No. SHO 64-80321 and Japanese Patent Application Laid-Open (Kokai) No. HEI 7-101492.
Depending of the place of installation, these storage box apparatuses may however be brought under substantially the same temperature environment as the external air. They are generally provided with rather thin heat-insulating layers in view of their installation spaces and moreover, the interiors have been in a hermetically-closed state before packages are placed. The interiors are considerably hot especially in summer during which the temperature of the external air is high.
A perishable such as meat is placed in the interior of such a hot temperature, and the power switch for the thermoelectric module is turned on. Since a conventional storage box apparatus is air-cooled on a heat-dissipating side, its interior cannot be cooled rapidly and moreover, tends to be affected by the external temperature, whereby its refrigerating function or freezing function cannot be exhibited to full extent. It is therefore accompanied by a drawback such that the freshness of perishables stored inside may be lowered and, when a delivered package is stored for a long time due to a trip or the like, its perishable content may spoil, thereby giving off a bad smell.